Additions to the Rotatoria of New Zealand. Part VI
[Read before the Canterbury Branch, November 4, 1953; received by the Editor, November 11, 1953.]
The author lists nine species of the Rotatoria and two varieties not previously recorded in New Zealand. It is suggested that some of the variations which authors have noted in species of Lepadella and Monostyla may be due to the influence of the mounting medium, of the preservative employed.
This paper lists nine species and two varieties of the Rotatoria not previously recorded in New Zealand One species found at Notornis Valley has previously been found only in Australia. Six of the rotifers listed belong to the genera Monostyla and Lepadella, the species of which are separated by small characteristics, and they all show slight differences from the types. Many of the old identifications were made from preserved or mounted material and it is suggested that some of the variations found by subsequent workers may be due to the influence of the preservatives employed, and the mounting media. Weakly loricated rotifers generally show the greatest differences from the types, and in any collection they are generally found in various degrees of contraction, particularly if the preservative has been added in a concentrated form: this may lead to erroneous conclusions. Preservatives, particularly formalin, is best added to samples in concentrations not exceeding 5 per cent. when the contractions should be moderately uniform.
In 1913 Harring published his “Synopsis of the Rotatoria,” which eliminated much of the earlier confusion on the classification and nomenclature of the Rotatoria; but in the forty years which have elapsed the position has again become unsatisfactory except in genera which have been revised. The proposals of Gillard (1948 and 1952) would, if generally adopted, do much to improve the systematics of the Rotatoria which, as many workers will affirm, is daily becoming more difficult.
Colurella colurus f. compressa (Lucks).
1912. Colurus colurus f. compressa Lucks. Zur Rotatorienfauna Westpreusens. Bot. zool. Ver. S. 1–2107. Danzig.
Locality. Brackish pools at South New Brighton, Canterbury. Temperature 15° C. Fairly common. Overall length of specimens, 154 microns. The specimens agreed with Lucks' description fairly well, but it is difficult to say if this form is a valid one until the genus is revised.
Euchlanis parva Rousselet, 1892.
Jour. Quekett Micr. Club. Ser. 2, vol. 4, p. 396.
Locality Tarn near the Kima Hut, Tararua Range, Wellington, where it was colleced by Miss B. A. Holloway, of the Dominion Museum. Not common.
Length of dorsal plate, 125 microns; of ventral plate, 115 microns.
Width of dorsal plate, 120 microns; of ventral plate, 80 microns.
Length of toes, 80 microns.
The ventral plate is the arc of a low circle. There was some variation between specimens in the width/length ratio of the dorsal plate, which was from 0.76–0.96.
Lepadella acuminata (Ehrenberg).
1834. Lepadella acuminata Ehrenberg. Abh. Akad. Wiss. Berlin, p. 210.
Locality. Seepage pools from Ashley River, Canterbury. Fairly common Temperature, 20° C. pH. 8. Total length, 110 microns. Length of lorica, 70 microns. Width, 70 microns. Length of toes and foot, 40 microns. This specimen differs considerably from those described by Hilgendorf (1898) from the mouth of the Taieri River. It has a sub-square dorsal sinus, and a fairly heavily stippled broad collar. The first foot joint is obscure. It is suggested that the animals found are merely fresh water variations of those described by Hilgendorf from brackish or marine habitats.
Lepadella patella (Muller).
1786. Brachionus patella Muller. Anim. Insuf., p. 341.
Locality. Swamp near Kiwi River, North Canterbury. Not common. Water probably acid. Total length, 112 microns. Length of lorica, 90 microns. Width of body, 70 microns. Anterior margin, 22 microns. Toes, 22 microns. The same species and typical specimens were also found in Lake Sarah by the Biological Department of Canterbury University College.
Lepadella vitrea (Shephard).
1892. Metopidia ovalis Shephard. Anderson and Shephard. Proc. Royal Soc. Victoria n. ser., vol. 4, p. 78. Not Metopidia ovalis (Muller).
Locality. Notornis Valley, South Westland, where it was collected in small numbers by Professor E. Percival. Total length, 114 microns; length of toes, 20 microns. This animal has previously been found only in Australia and differs from the type in dimensions, and in having a series of dots round the lateral edge of the dorsal plate. No collar was found.
Monostyla arcuata Bryce, 1891.
Science Gossip. Vol. 22, p. 206.
Locality. Weedy pools on the north side of the Ashley River, Canterbury. Fairly common. Temperature, 18° C., pH. 8. Total length, 110 microns This small variety differs from those found in acid waters. The body is oval and the anterior dorsal margin is straight.
Monostyla hamata Stokes, 1896.
Ann. Mag. Nat. Hist. Series 6, vol. 18, p. 21.
Locality. Swamp near Kiwi Stream, North Canterbury. Water probably acid. Not common. Total length, 96 microns. The specimens were typical and except in size were similar to those found on the Chatham Islands (Russell, 1953).
Monostyla rugosa Harring, 1914.
Proc. U.S. Nat. Museum. Vol. 7, p. 548.
Locality. Collected by Professor Percival from Notornis Valley. Not common. Total length, 90 microns. Typical specimens except for the facetting, which may be obscure or absent.
Polyarthra vulgaris Carlin, 1943.
Die Planktonrotatorien des Motalastrom. Lunds Universitets Limnologiska Inst. Lund, p. 105.
Locality. Lake Taylor, North Canterbury. Length of lorica, 100 microns; width, 70 microns. Not common. Most of the specimens of Polyarthra have been referred to the two species trigla, and euryptera, but in 1943 Carlin revised the genus and showed that there were about seven separate species. Gillard (1952) has also published a valuable monograph on the genus Polyarthra. Specimens of the genus from New Zealand previously described as trigla will have to be re-examined, and probably re-classified.
Proales dollaris (Rousselet).
1895. Micrococodidcs dollaris Rousselet. Jour. Quekett. Micr. Club. Ser. 2, vol. 6, p. 120.
Locality. Tarn near Kima Hut, Tararua Range, Wellington, at an altitude of 4,616 feet, where it was collected by Miss B. A. Holloway, of the Dominion Museum. Common. Total length, 200 microns; width, 100 microns; toes, 20 microns. The mastax is of an aberrant form, and it appears doubtful whether this species should be included in the genus Proales.
Testudinella incisa (Ternetz).
1892. Pterodina incisa Ternetz. Rotat. Umg. Basels., pp. 20, 41.
Locality. Notornis Valley, South Westland, where it was collected by Professor E. Percival. Rare. The anterior mucrone has a distinct V notch, and the dorsal markings which are probably shallow folds, follow the contour of the plate. Total length, 92 microns; width, 88 microns.
The rotifers listed in this paper in many cases come from inaccessible habitats in widely separated parts of the Dominion, and I am greatly indebted to those who often at considerable inconvenience to themselves, have brought me samples. In particular, I tender my thanks to Professor E. Percival, of Canterbury University College; Miss B. A. Holloway, of the Dominion Museum; Mr. H. Talbot, of Springfield; and Mr. W. Dukes, of Christchurch, all of whom have sent me valuable material during 1952 and 1953.
Gillard, A., 1948. De Brachionidae van Belgie Beschouwingen over de Taxonomic van de femilie. Natuurwet Tijdschr, 30. Gent.
— 1952. Bijdrage tot de studie der Raderdierfauna van Belgie. Bijkslandbouwhogeschool. Gent.
Harring, H. K., 1913. Synopsis of the Rotatoria. Bull. 81, Smithsonian Institute, Washington.
Hilgendorf, F. W., 1898. A Contribution to the Rotifera of New Zealand. Proc. N. Z. Inst., vol. 31, pp. 107–24.
Russell, C. R., 1953. Some Rotatoria of the Chatham Islands. Canterbury Museum Records, vol. 6, no. 3.